Pyelogram (or pyelography or urography) is a form of imaging of the renal pelvis and ureter. Types include: Intravenous pyelogram – In which a contrast solution is introduced through a vein into the circulatory system. Retrograde pyelogram – Any pyelogram in which contrast medium is introduced from the lower urinary tract and flows toward the kidney (i.e. in a "retrograde" direction, against the normal flow of urine). Anterograde pyelogram (also antegrade pyelogram) – A pyelogram where a contrast medium passes from the kidneys toward the bladder, mimicking the normal flow of urine. Gas pyelogram – A pyelogram that uses a gaseous rather than liquid contrast medium. It may also form without the injection of a gas, when gas producing micro-organisms infect the most upper parts of urinary system. Intravenous pyelogram An intravenous pyelogram (IVP), also called an intravenous urogram (IVU), is a radiological procedure used to visualize abnormalities of the urinary system, including the kidneys, ureters, and bladder. Unlike a kidneys, ureters, and bladder x-ray (KUB), which is a plain (that is, noncontrast) radiograph, an IVP uses contrast to highlight the urinary tract. In IVP, the contrast agent is given through a vein (intravenously), allowed to be cleared by the kidneys and excreted through the urinary tract as part of the urine. If this is contraindicated for some reason, a retrograde pyelogram, with the contrast flowing upstream, can be done instead. Uses An intravenous pyelogram is used to look for problems relating to the urinary tract. These may include blockages or narrowing, such as due to kidney stones, cancer (such as renal cell carcinoma or transitional cell carcinoma), enlarged prostate glands, and anatomical variations, such as a medullary sponge kidney. They may also be able to show evidence of chronic scarring due to recurrent urinary tract infections, and to assess for cysts associated with polycystic kidney disease. Obstruction (commonly at the pelvic-ureteric junction or PUJ and the vesicoureteric junction or VUJ) Procedure An injection of X-ray contrast medium is given to a patient via a needle or cannula into the vein, typically in the antecubital fossa of arm. The contrast is excreted or removed from the bloodstream via the kidneys, and the contrast media becomes visible on X-rays almost immediately after injection. X-rays are taken at specific time intervals to capture the contrast as it travels through the different parts of the urinary system. At the end of the test,